This invention relates to sliders for slide fasteners and more particularly to a slide fastener slider of the character which is suitable for mounting on and manipulating such heavy duty slide fasteners which are applied to joints in partition members such for example as oil fences or seams in hoods for use with trains or automobiles.
The slider for the heavy duty slide fasteners just described has been required, while closing the slide fastener, to be firmly retained in locked relation with respect to a pair of fastener stringers against severe stresses exerted on or around the slider. In order to meet this requirement, the prior art slider has been provided with a locking prong secured to or formed integrally with a pull tab pivotally connected to the slider body, which locking prong is adapted to engage with fastener elements mounted on a fastener stringer in order to lock the slider against movement along the fastener stringers. A pair of pull tabs have been employed which are adapted to be releasably joined at ends to maintain the prong in locking engagement with fastener elements. However, there has been experienced a difficulty such that conventional locking prongs are liable to disengage from fastener elements when subject to severe external stresses even with the aid of joined pull tabs because the prongs are so disposed as to easily become subjected to the external stresses.